1. Field of the Invention
The present invention is related to communication devices capable of being connected via a serial communication line to devices such as personal computers to provide communication via telephone lines and, more particularly, to a serial communication device capable of transmitting and receiving both facsimile images and ASCII characters and including the ability to convert ASCII characters into facsimile images.
2. Description of the Related Art
At the present time there is widespread use of communication devices known as modems in conjunction with computer terminals, personal computers and larger computers. These modems typically transmit data using the American Standard Character Interchange Interface (ASCII) codes with or without compression or additional encoding. There is also widespread use of facsimile machines which scan a sheet of text or graphics to produce scan encoded data that is transmitted via telephone lines to another facsimile machine where a facsimile of the sheet is printed. Most facsimile machines in use today are classified as Group 3 machines as defined by the Consultative Committee for International Telephone and Telegraph (CCITT) and use Modified Huffman (MH) run length codes representing black and white pixels. Recently, communication devices have been made available to transmit and receive scan encoded data from and to a personal computer. Some of the communication devices which allow personal computers to transmit and receive scan encoded data also provide conventional ASCII text communication capability, i.e., operate as a modem.
There are currently two methods for generating scan encoded data for transmission from a personal computer. The first method is to scan a document in the conventional way, either using an optical scanner connected to the personal computer, or by using a stand-alone facsimile machine to transmit a facsimile image to the computer. In either case, the scanned image is received by the personal computer and stored for subsequent transmission. The second method is to use software on the personal computer to convert text or graphics stored in other formats into scan encoded data for transmission. This obviously requires additional processing by the personal computer in addition to the time required to transmit the scan encoded data to a facsimile machine or another personal computer.